The invention relates to non-electrical detonators operated by a fuse driving a striking pin to fire a percussion cap.
More particularly, the invention relates to a detonator assembly which contains a main charge, initial charge, and a delay element. The charges are fired by a percussion cap which is in a unique assembly operated by a double ended striking pin movable against a compressible spherical body and operated by the pressure of the fuse.
A detonator of this type is disclosed in European Patent EP-A1 0253955, particularly in FIG. 4 of the patent. In this structure if the fuse or the primer tube, that is, the chemical substance contained therein is ignited, the resultant pressure wave propagates at high velocity and propels the striking pin against the percussion cap whereupon the igniter is detonated. The striking pin in this arrangement is guided partially in the fuse and partially in the percussion cap retainer.
However, this arrangement has proven disadvantageous in certain aspects such as when the detonator is assembled and crimped, which is accomplished by insertion of the fuse in the sleeve employed in an interposed elastic plug and subsequent deformation of the sleeve, a fuse section may then also become restricted resulting in inhibition of the mobility of the striking pin. This, of course, can make the detonator become ineffective. Moreover, the effective surface area of the striking pin upon which the gas pressure of the fuse can act is limited to the clear cross section of the fuse.